Measuring CFM?

[KirbysNphones]

I was wondering what tool or meter would be used for measuring CFM for vacuums? I'm not having much luck finding one. The only one I know of is the Baird meter, and I only found one place that even sells them! (goodvac, I think) Plus, the Baird is just a scale of 1-10, not CFM afaik.

And also what are some of the vacs with the best performance in terms of CFM or water lift?

Thanks!

 

[sebo_fan]

Ive been led to believe that even if a vacuum has high CFM it doesn't ensure success or offer best performance - again like air watts, its all about whether the vacuum in question has a sealed suction unit.

 

[electromatik]

I went to Google and typed in "measuring air flow CFM" and one of the sponsored links on the right was advertising a CFM air flow meter at Home Depot for $649.00. They must carry them, but perhaps only online. Vacuum experts say that this is important to a vac's performance and so is water lift and brushroll speed, design, etc. The three act in tandem to clean. Most companies use a little trickery to brag about air flow and water lift. They are measured at the vacuum opening, not at the end of the nozzle/hose/etc. However, it remains a fact of nature that the higher the water lift and air flow numbers, the better it will perform with the filters, bag, and hose in place. You must have strong suction to lift dirt from deep in carpeting.

Some of the most powerful household vacuum's in terms of water lift are Aerus Lux Guardian Platinum, Riccar Immaculate, Miele's S8 series, and probably Filter Queen and SEBO also. The Aerus, Riccar, and Miele have water lift's of 100" or better. I am not familiar with SEBO and Filter Queen's number right away. Rexair Rainbow is equipped with 90-95" water lift and never loses it. All these are canister cleaners of course, which are far more powerful than upright cleaners. And of course the Kirby is also very powerful for an upright vacuum but it won't approach these (and it doesn't need to as it is a direct air upright). It used to be that water lift numbers above 100" were unheard of in anything other than central vacs, but the gap is closing all the time. Technology now exists to place huge motors in canisters and still remain fairly quiet. I hope one day soon we will see canisters at 150"! LOL

 

[KirbysNphones]

150" water lift and 100 CFM! and $600+ for a meter is just ridiculous, as the Baird meter was like $50 on Goodvac!

I can see how CFM and water lift would be in tandem, just like volts, watts and amps. Also, the design of the fan would add to this too, you could put an industrial 3 phase motor with insane RPM on a crappy fan, and not get good suction, whereas a decent 120 volt motor with a well designed fan assembly would do better.

 

[blackheart]

In terms of CFM

you cannot be a direct air machine i have a baird meter the kirby G6 measures in at a 10 at the fan a 7 at the end of a hose

The most powerful canister i've measured was the Kenmore Magic Blue which also pulled a 10/10 i was shocked

I've measured some of the vacs i have if you are interested here's what i have recorded
Vita vac (airway) with the Airtech cloth bags pulls a 6 with paper 4
Dirt Devil Deluxe 3/10
Dyson DC-11 2/10
Dyson DC-17 1.5/10
Electrolux olympia 4.5/10
Hoover Celebrity II Elite 3/10
Hoover Windtunnel Plus 8/10
Lindhaus Aria Platinum (measured at a vac store 6.5/10
Miele Silver Moon 5/10
Patriot 5.5/10
Riccar 1700 5.5/10
Royal Classic Power Tank 2.5/10
Simplicity 7 series 7.5/10
Silver King Blue max 3
Thermax AF1 .5
Tristar CXL 5
Tristar CXL 5

I know i have measured others but i cannot recall their numbers

 

[KirbysNphones]

Cool info Blackheart! Now I need to get myself a Baird Meter and see what my Filter Queens do, as well as my older Kirbys

 

[a007kirbyman]

kirbysnphones (Will) & Baird AirFlo Meter...

Hello Will.

If you haven't already acquired the Baird AirFlo Meter elsewhere, shoot me an email. I sent you an email with my contact info.

If you have, keep me in mind next time as a source for your Genuine Kirby wants & needs. I'm sure I will be able to save you substantially.

I carry only Genuine Kirby parts.

I can do new (or demoed/used, currently) & $ave you $$$ vs. posted above amount.

Cheers & hagr8wknd all,

Bill

 

[crock]

The issue is that you need to measure both airflow and inches of water at the same time to get a good idea of a vacuum's ability. As was said earlier the brush roll and the seal are also factors that determine the vacuum's performance. The Baird meter is a combination of CFM and inches water that gives a performance rating on Baird's proprietary 1-10 scale.It is a pretty good system and useful because so many others in the vacuum industry use it as a standard.If you want to compare airflow between different vacuum's you need to do so at a standard inches of water height suction. So you might choose 30 inches of water to compare all the vacuum's airflow in Cubic Feet Per Minute (CFM). The cheapest instrument that will do this a rotary vane airflow meter. They cost around $300 new and around $100 on Ebay. You would be looking for one that operated in the 20-100 CFM airflow rate. You also need a manometer to set the vacuum's "pull" at 30 Inches of Water.The Manometer runs another $100 on Ebay. So you can see, measuring the airflow is not a cheap proposition. To compare vacuums you must measure the airflow at the same inches of water height suction. Since there is no standard for the inches of water height suction between manufacturers, comparing manufacturer claims for airflow is pretty much worthless.

 

[blackheart]

Okay some more numbers

Dirt Devil Deluxe 3/10
Dirt Devil Pro series powerpak canvac 1/10 (it does have bearing issues but i don't know exactly how much this would effect it's performance)
Dyson DC-07 2 (side port leading to diverter)
Electrolux 3500 SR 0/10 (hose)
Electrolux Olympia 3.5
Filter Queen Triple Crown 4/10
Filter Queen 75th anniversary 2.5/10
Filtropur 0.5/10
Hoover Dial a matic 2.5 (tool port) 1 (hose to brushroll)
Kirby Heritage 5/10 (hose)
Lindhaus Activa 0/10
Lindhaus Healthcare Pro 2.5/10
Oreck Buster B 0/10
Panasonic Jetflo 0/10 (old bag no new ones on hand)
Rainbow D3 0/10 (tried with both non electric and D4 hose)
Rainbow D4 SE 0/10
Sebo 370 2/10
Tristar EXL 4.5/10
Tristar MG2 1.5/10
Windsor Sensor S12 0/10

I found the tristars quite shocking the EXL has a dual stage motor and just destroyed the single stage (VM3 if i do recall) MG1 in terms of airflow

 

[dysonman1]

The Baird Meter was designed to make a Kirby look good. There are actual airflow meters used by manufacturers, as well as electronic water lift gauges. The airflow meter is actually a digital wind speed meter. There's a little fan inside that's turned by the airflow and the digital readout is absolutely accurate. Both of these instruments are very expensive.

The Vacuum Collectors Convention is starting tomorrow at the Vacuum Cleaner Museum here in St. James. After the tour of the factory, I'm taking everyone into the testing labs, and we'll actually get accurate reading of many cleaners, new and vintage. I'll post pics of the results in a separate picture thread about the Convention tomorrow.

 

[blackheart]

That will be interesting

Looking forward to seeing it Tom.

 

[beerad]

Filter-Queen

Does 85 - 90 cfm average.

 

[kenkart]

Of the old cleaners..

1950s and 60s vintage, the Apex Strato Cleaner and Sunbeam dual deluxe will pull the Baird meter all the way back with a SNAP! at the machine, I dont know about the end of hose performance.

 

[123go]

Well where are they?

So' Im guessing all the super duper testing after the collectors convention never happened? I dont see a link & I cant find anything? Did they all just fail these tests or what?..lol

 

[123go]

So old Vac pics get lost for good? Ive not found a single pic here yet?

 

[mjhoshaw]

So old Vac pics get lost for good? Ive not found a single pic here yet?

If you haven't already discovered this, look at Media starting on page 2. The pics are there, just not in a one-per-day format.

 

[123go]

If you haven't already discovered this, look at Media starting on page 2. The pics are there, just not in a one-per-day format.

Found' Thank you!

 

[cheesewonton]

Here is something all these people testing vacuums are missing about airflow. An anemometer can only measure airspeed. It has to compute airflow. To do so accurately the anemometer has to know the inside diameter and/or the surface area of the orifice or duct you are measuring the airflow of. Most testers use a little propeller style anemometer and every single one of those grossly overestimates actual airflow since it's calculation is based on the diameter of the little fan and not on the diameter of the hose and hose spout.

I have a digital hot wire anemometer. They are more expensive but I got a deal on one for a smidge over $200. It normally retails for $700. On this instrument you have to enter the surface area in square feet of the opening through which the air is flowing. A shortcoming of this meter is that it is really designed for HVAC and not for measuring vacuum cleaner airflow. The smallest opening you can enter on the screen is 0.01 square feet. A 1 1/4 inch diameter hose has an opening of 0.0088 square feet What that means is that even setting my meter to the smallest opening I am over estimating airflow on vacuums with standard 1 1/4 inch hoses. Even still I typically measure much lower CFM airflow readings than others with the propeller anemometer do. A 35 mm hose end has an opening of 0.0104 square feet so I can measure a Miele accurately. For larger hoses like modern Kennys and some of my Japanese vacuums I have to choose 0.02 square feet on my meter to get a more accurate measurement.

I also collect the data sheets for vacuum motors to see what their suction and airflow ratings are. I often see figures posted for both airflow and sealed suction for vacuums that exceed the manufacturers ratings for the motor installed in that vacuum. I have to think this is due to using less expensive instruments and maybe inadequate technique. Not trying to be disparaging because I am still working on how to make my own measurements more accurate, thinking I need to contact the manufacturer of the anemometer to suggest factors to use for the many sized hose ends of the vacuums in my collection, running from 28 mm ( Tristar, Miracle Mate, Patriot ) up to the big 46-48 mm sewer pipes on some of my Panasonic and Hitachi models from Japan.

To get an idea what I see, my highest airflow measurement so far is from a big Swedish Electrolux D795 and that was 77 cfm. The highest suction I have measured is a tie between a Kenmore Elite and my Riccar 1700 at 92 inches measured at the hose end ( only way you can turn them on ) but the Riccar only gives a meh 57 cfm. Most vacuums have much less on my instruments. Example, my brand new VAPamore ( Crapamore ) MR500 pulled 88 inches of suction at the hose end and 57 cfm. Most of my Tristars regardless of vintage only pull 62-64 inches of suction and 52 cfm. Doesn't seem to matter what motor I stuff in a Tristar, they all give 52 cfm . The 28 mm ID hose is just too small. My immaculate old Miele S558 pulls 60 inches of suction and 64 cfm, a bit less than an old Kenmore Whispertone gives.

 

[cheesewonton]

Ive been led to believe that even if a vacuum has high CFM it doesn't ensure success or offer best performance - again like air watts, its all about whether the vacuum in question has a sealed suction unit.

Try using a Kirby on the hose to dust with. Miserable. It doesn't pick anything up. 30 inches of sealed suction for my Avalir 2.

 

[panasonicvac]

Many years ago my old local vacuum store had a suction meter similar to this shop down below. I remember back in 2012, my buddy showed me a demonstration between a Panasonic Platinum QuietForce MC-UG729 to a Sanitaire S645 Type A, it was a night and day difference. The Panasonic I think got a mixture of SORRY and POOR ratings while the Sanitaire went all the way up to the WOW rating. Despite that test, I still like the Panasonic more than the Sanitaire. I don't know who made those suction meters but I'd love to find one to play around with just for fun. I may not care much about the actual numbers but something like that meter gives me a better idea of just how much airflow any machine has on the nozzle.

 

[blackheart]

Ha! I like that scale. Would have been a good sales tool.

 

[cheesewonton]

Many years ago my old local vacuum store had a suction meter similar to this shop down below. I remember back in 2012, my buddy showed me a demonstration between a Panasonic Platinum QuietForce MC-UG729 to a Sanitaire S645 Type A, it was a night and day difference. The Panasonic I think got a mixture of SORRY and POOR ratings while the Sanitaire went all the way up to the WOW rating. Despite that test, I still like the Panasonic more than the Sanitaire. I don't know who made those suction meters but I'd love to find one to play around with just for fun. I may not care much about the actual numbers but something like that meter gives me a better idea of just how much airflow any machine has on the nozzle.

Have a look at his video from Vacuum Wars where they test a selection of direct air and clean air commercial uprights. The Sanitaire Tradition had the highest airflow by far, but they have low sealed suction compared to the clean air machines. Not seeing the test you refer to I can't comment on the nature of the test procedure, how they measured sealed suction on a direct air vacuum with no hose, the test equipment used or the condition of the vacuums tested. This Vacuum Wars test is a test of new vacuums. My only criticism is the anemometer they use is not accurate, it reads overly high airflows, but for comparing machines it is acceptable.



I have a Hushtone and like it except for the lack of a synthetic HEPA dust bag. I have been fooling around with other kinds of HEPA dust bags to see what might fit the Hoover mount. Stay tuned.

 

[vaclab]

Try using a Kirby on the hose to dust with. Miserable. It doesn't pick anything up. 30 inches of sealed suction for my Avalir 2.

Miserable to dust with? That's crazy talk. 120 hose CFM picks up dust fabulously. And suction barely matters as I have conclusively proven since 2017 on my YouTube channel.

1) Suction is a one dimensional pressure, not a movement or a volume. Suction doesn't pickup anything (in the air).
2) Airflow is the speed of a volume of air and transports the dirt from point "A" to point "B".
3) Vacuums with little to zero measured nozzle suction can pick up dirt.
4) Airwatts are one of the many false attempts of manufacturers to sell vacuum based on useless data.

AirWatts Suction And Airflow Explanation


Congrats on your hotwire anemometer, but never forget that cheaper units (using fan blades) can measure CFM (indirectly) just fine. Are you aware that some of them have built-in functionality that actually produces a CFM number? I have one. I also have a super cheap model that requires one simple ratio calculation to convert ft./min to CFM.

If you want to see how to build a proper (cheap) airflow box and obtain accurate airflow/suction readings, check out my YouTube channel.

 

[vaclab]

Here's my fully measured TriStar CXL. It does have a 10-Amp motor in it though.

 

[cheesewonton]

Here is a great example of why those fan style anemometers are so inaccurate. You claim 132 cfm at the hose connection. The motor in a CXL cannot produce that much airflow. Airflow in a vacuum motor is dependent on the size of the orifice. Vacuum motors make maximum airflow at a 2 inch or 50 mm opening. As you reduce the diameter of the orifice airflow is reduced. The OEM motor in a CXL is Ametek 116884-49. I have the Product Bulletin pdf open for that motor and will try to attach it but no guarantees it will load. Anyhoo, the maximum airflow at a wide open orifice for that motor is 115 cfm. That's it. The hose opening on a CXL is 28 mm or 1.1 inch measured with my caliper. Looking at the Ametek Product Bulletin at a 1.125 inch orifice that motor produces 90.7 cfm. That is all the motor can produce. It is physically impossible for the motor in that CXL to produce 132 cfm at the hose opening. In fact very few vacuum motors that are safe to use on a standard household 12 amp circuit make 132 cfm at an unrestricted orifice much less at the tiny 1.1 inch opening Tristar, Miracle Mate and Patriot use.

Here is how to think about how airflow is calculated by an anemometer. Think of a long tube filled with some fluid. The tube is moving at a certain velocity. The volume of fluid passing a point depends on the size of the tube, its velocity and the time period. The only thing any anemometer measures directly is the velocity. But lets say you want to know the volume of liquid that passes by the anemometer in a given time. Airflow is measured in units of volume multiplied by time, cubic feet ( volume ) per minute. Imagine your tube full of liquid flowing past your anemometer. The anemometer only knows how fast it is going. The tube could be 1/4 inch diameter or 2 inches diameter and the anemometer could not sense the difference. But for a given velocity the 2 inch diameter tube will pass a lot more volume past the anemometer in a given period of time than the 1/4 inch tube. That difference in diameter matters. But for anemometers that are used for commercial HVAC, most of the time the ducts are square or rectangular, so the meter I have requires the user to enter the surface area of the opening ( imagine a square tube filled with air rather than a round one flowing past the anemometer ) so the anemometer can accurately calculate airflow. Those propeller anemometers use the surface area of the round opening the propeller sits in, but that opening is a lot larger than the diameter of any vacuum hose so the readings it gives for vacuums are wildly inaccurate and almost always too high.

 

[cheesewonton]

All of my various Tristars, DXL, EX-30, MG and my modified models ( different motors and in the case of modern Tristar bodies I hog out the plastic exhaust port so you can no longer connect a hose to it as a blower but I leave enough material to attach the exhaust filter ) produce the same airflow. 52 cfm measured at the hose end and this measurement is a bit higher than it really is due to the limitations of my anemometer mentioned earlier. I can use the 356 peak air watt OEM motor, a nice Electromotor replacement motor the 6500-298 rated at 438 air watts, or a modern motor from a Pro Team Supercoach backpack vac, the Ametek 119347-01 rated at 489 peak air watts ( and 140 cfm at a wide open orifice ) and it doesn't seem to change anything. They all produce 52 cfm at the hose end and low to mid 60 inch water lift ( boy you can hear the air hissing past the hose swivel on modern Tristars ! ). The only motor I have tried that gave a marginally better result was a Panasonic 3D Inducer motor from a Kenmore Elite, a 600 air watt beast that gives cfm airflows into the 70s on Kenmores. I modified a CS motor mount and put one in a modern Tristar body. On the Tristar it produces 56 cfm. Big whoop.

 

[vaclab]

Ohhhh boy, dude. Re-read my statement:

Today at 8:55 AM #24
Here's my fully measured TriStar CXL. It does have a 10-Amp motor in it though.

That's not the original motor! The original motor (6 Amps) would be MUCH weaker obviously.

Wanna see what a central vacuum grade motor (12 Amps) can do in an old canister? Check this out:

 

[panasonicvac]

Have a look at his video from Vacuum Wars where they test a selection of direct air and clean air commercial uprights. The Sanitaire Tradition had the highest airflow by far, but they have low sealed suction compared to the clean air machines. Not seeing the test you refer to I can't comment on the nature of the test procedure, how they measured sealed suction on a direct air vacuum with no hose, the test equipment used or the condition of the vacuums tested. This Vacuum Wars test is a test of new vacuums. My only criticism is the anemometer they use is not accurate, it reads overly high airflows, but for comparing machines it is acceptable.



I have a Hushtone and like it except for the lack of a synthetic HEPA dust bag. I have been fooling around with other kinds of HEPA dust bags to see what might fit the Hoover mount. Stay tuned.

VW's tests are so misleading, that's one of the reasons why I don't watch his channel anymore. Bill (VacLab) gives a more thorough explanation in his posts and videos which makes more sense to me.

 

[cheesewonton]

Ohhhh boy, dude. Re-read my statement:

Today at 8:55 AM #24
Here's my fully measured TriStar CXL. It does have a 10-Amp motor in it though.

That's not the original motor! The original motor (6 Amps) would be MUCH weaker obviously.

Wanna see what a central vacuum grade motor (12 Amps) can do in an old canister? Check this out:

View attachment 168395

All I am saying is that you are using an inaccurate anemometer to measure airflow. It is giving a false high reading because it is calculating airflow based on the diameter of that fan, which is larger than the diameter of any opening on any vacuum except for shop vacs with 2 inch hoses.

Tell us what motor you are using and I will dig up the data sheet for it and see if it can really produce 146 cfm through a 1 1/4 inch orifice. A Perfect C101 is the same vacuum as the Marquis other than their motors and motor housings and the Perfect thankfully doesn't have the automatic bag door "feature". You can literally swap parts between them and most aftermarket parts fit both. The motor used in the Perfect C101, Ametek 122093 is rated at 557 peak air watts, pulls 13.2 amps ( which is probably why they burn up wiring and connectors ! ) and is rated for a maximum airflow of 123.8 cfm. The C101 generates 77 cfm at the hose end on my anemometer. Unless I see a data sheet that says otherwise I am doubtful any 12 amp suction motor can generate 146 cfm through a 1 1/4 inch opening or 115 cfm at the end of a standard 1 1/4 inch hose.

 

[cheesewonton]

Btw, if you are using the 10 amp Ametek 115923 motor in the CXL, it's maximum rated airflow is 122 cfm at a 2 inch orifice. I have that motor in my DXL and all it gives at the hose end is 52 cfm, same as every other motor I have tried in one. And that is with no exhaust filter, just the little diffuser.